Why does my team keep missing deadlines?

What is the planning fallacy?

Buehler, Griffin and Ross (1994) tested it across a range of academic and non-academic tasks. Participants' predictions of how long a task would take were too optimistic. They underestimated their own completion times but not other people's. Think-aloud records showed that they concentrated on future scenarios for the task and paid little attention to relevant past experience.

In one of their studies, the optimistic bias disappeared when people were told to link relevant past experiences to their predictions.

Does the same thing happen in organisations?

Flyvbjerg (2021) lists the planning fallacy among the ten behavioural biases that matter most in project management, alongside optimism bias and overconfidence. He argues that base rate neglect, which means ignoring how comparable projects have turned out, is a primary reason projects underperform, and he presents base rates from 2,062 projects. His data come from projects, which are larger than most team tasks, so read the finding as a pointer and not a measurement of your team.

He also argues that cognitive bias is half the story and political bias the other half. Forecasts can be shaped by what people think will be approved as well as by what they believe.

What does the research suggest teams can do?

• Take the outside view. Lovallo and Kahneman (2003) recommend looking at the experiences of a class of similar projects and placing the current one in that distribution. This is often called reference-class forecasting.
• Connect estimates to past experience. This is the manipulation that removed the bias in Buehler and colleagues' fourth study.
• Write if-then plans. A meta-analysis by Gollwitzer and Sheeran (2006) covering 94 independent tests and more than 8,000 participants found that implementation intentions had a medium to large positive effect on goal attainment. That review is about goals in general, so it is a lead worth testing and not proof about deadlines.

These are practices from the research literature. They are not KOZMO's method.

What if the answer sits in how my own team works?

The studies above describe how people in general think about time. They cannot tell you which of your own working habits matter. The Snapshot shows what stands out in how you work, and it is a sensible place to start.

Where does this come from?

Buehler, R., Griffin, D. & Ross, M. (1994). Exploring the "planning fallacy": why people underestimate their task completion times. Journal of Personality and Social Psychology, 67(3), 366-381.

Flyvbjerg, B. (2021). Top ten behavioral biases in project management: an overview. Project Management Journal, 52(6), 531-546. Open copy (arXiv) · doi:10.1177/87569728211049046

Lovallo, D. & Kahneman, D. (2003). Delusions of success: how optimism undermines executives' decisions. Harvard Business Review, 81(7), 56-63.

Gollwitzer, P. M. & Sheeran, P. (2006). Implementation intentions and goal achievement: a meta-analysis of effects and processes. Advances in Experimental Social Psychology, 38, 69-119. doi:10.1016/S0065-2601(06)38002-1